Just paste in <system.web> of web.config or machine.config:
<browserCaps>
<case match="^Mozilla/5\.0 \([^)]*\) (Gecko/[-\d]+)(?'VendorProductToken'
(?'type'[^/\d]*)([\d]*)/(?'version'(?'major'\d+)(?'minor'\.\d+)(?'letters'\w*)))?">
browser=Gecko
<filter>
<case match="(Gecko/[-\d]+)(?'VendorProductToken'
(?'type'[^/\d]*)([\d]*)/(?'version'(?'major'\d+)(?'minor'\.\d+)(?'letters'\w*)))">
type=${type}
</case>
<case> <!-- plain Mozilla if no VendorProductToken found -->
type=Mozilla
</case>
</filter>
frames=true
tables=true
cookies=true
javascript=true
javaapplets=true
ecmascriptversion=1.5
w3cdomversion=1.0
css1=true
css2=true
xml=true
tagwriter=System.Web.UI.HtmlTextWriter
<case match="rv:(?'version'(?'major'\d+)(?'minor'\.\d+)(?'letters'\w*))">
version=${version}
majorversion=0${major}
minorversion=0${minor}
<case match="^b" with="${letters}">
beta=true
</case>
</case>
</case>
</browserCaps>
